Sunday, January 6, 2013

RealD vs. Imax Digital 3D: What’s the Difference?

3D movies are
quite common these days, with many of the latest animated films, action-packed
blockbusters and horror flicks being presented with a third-dimension. The
passive polarizing technology used to display 3D in most movie theaters is also
similar to those found in passive 3D TVs. However, the fact that some movies are
presented in several 3D formats in the theaters can be somewhat confusing.

Most of us who’ve caught a 3D movie at the
cinemas recently probably experienced the more common RealD 3D technology,
while Imax Digital 3D (as well as its analog counterpart)
is a format presented at Imax auditoriums. But is there any difference between
RealD 3D and Imax Digital 3D?

Here’s what we
know.

First, the
similarities

RealD 3D and Imax
Digital 3D both utilize passive 3D technology, which makes use of relatively
lightweight eyewear. These passive 3D glasses use polarizing filters to allow
each eye to see a slightly different image. This is why the glasses can
sometimes seem darker in one eye than the other–it’s meant to block out certain
spectrums of light. The glasses at Imax theaters are larger, to compensate for the
larger field-of-view at those auditoriums.

Both these
technologies are also digital, which means that you’ll get a clean image and
none of the image noise or “cigarette burns” that are visible from regular film
projectors.

How they compare

RealD 3D

The prevalent
technology in 3D cinemas worldwide comes from RealD, an American company
founded in 2003. The RealD 3D format is natively digital. This means that
movies have to be produced in a digital 3D format for projection on film-less
digital projectors. RealD cinemas also use a passive circular polarizing
technique to achieve 3D which allows viewers a clear image even when turning or
tilting their heads. Passive 3D TVs use circular polarizing technology,
too. The first RealD 3D movie screened was Chicken Little in 2005.

Imax Digital 3D

This is a
competing format that’s been around for a little longer. Imax cinema
auditoriums are well known for their massive, curved screens, which fill a
larger portion of your field-of-vision (FOV), or how much much your eyes can see a any one time.

An Imax auditorium in Singapore. (Credit: Shaw Theaters)

Imax Digital 3D is
an evolutionary improvement of the analog Imax 3D theaters that have been
around since 1986. Its long history is evident even in the much newer Imax
Digital 3D theaters since they still utilize the linear polarizing technology
of its analog predecessors. Unlike RealD, Imax 3D movies are less tolerant of
head movements. Viewers have to avoid tilting their heads, though some
turning–probably unavoidable due to the massive Imax screen format–is possible.
Also, Imax screens are curved to fill an audience member’s FOV, which enhances
immersion while giving those sitting at the sides a better view of the action.
Imax Digital auditoriums also use two 2K projectors for 3D shows, which leads to a visibly brighter image through the glasses.

While many Imax
theaters these days are digital, there are still auditoriums with the analog
Imax 3D format in the US and some other countries. These auditoriums typically
have a larger screen and correspondingly large projection equipment and tend to
be used for documentaries instead of feature films, too. Omnimax theaters
(recently renamed as IMAX Dome) are a variation of this analog format, but have a dome-shaped screen.

Why do Imax
Digital 3D movies cost more?

3D ticket prices
vary across Asia but Imax Digital 3D tickets typically cost more than their
RealD 3D counterparts. In Singapore, a weekday ticket to a new movie at theLido Cineplex starts at S$19 on Imax Digital 3D while
the average cinema with RealD 3D charges S$12 on average. At an AMC cinema in
Los Angeles, a typical Imax Digital 3D movie starts at about US$12, while the
same movie on RealD 3D would be about US$2 cheaper.

Theater audiences
are paying more for Imax 3D movies for a few possible reasons. The first would
be the consistent audio and visual quality across Imax auditoriums, the
generally larger screen (that’s at a closer proximity to the audience) as well
as a brighter image from the dual-projectors.

Of course, certain
cinemas that use the RealD format for 3D screenings do have other selling
points such as sharper 4K projectors, or better sound. An example of the latter
would be auditoriums with Dolby Atmos setups, which can present more believable
surround sound effects.

Just the facts

Aside from the
larger screen size, there are other notable differences between Imax Digital 3D
and RealD 3D. RealD 3D projectors like Sony’s 4K Digital Cinema models use a special lens to
project 3D visuals, which can provide viewers with up to four times the
resolution of full-HD 1080p. However, not all RealD 3D auditoriums have 4K
projectors–many feature 2K digital projectors–so you may have to check with
your favorite cinema chain’s Web site to find out which they use.

All Imax Digital 3D theaters, on the other hand, use Christie
2K dual-projector systems, which give twice the resolution of full-HD and a
brighter 3D image. What this means is that RealD 3D auditoriums with 4K
projectors can provide a visibly sharper image, especially with movies shot on
similarly high-resolution cameras.

Imax Digital 3D

RealD 3D

3D technology

Linear
polarizing

Circular
polarizing

Projector

Dual projectors

Single projector
(with 3D lens)

Screen

Silver coated

Silver coated

3D glasses

Large format
(for larger screen)

Standard size

Audio

Uncompressed

Varies by
theater

The 3D effect

A scene from sci-fi movie Prometheus, which
was shot in 3D and released on Imax 3D and RealD 3D screens. (Credit: Twentieth
Century Fox)

To some, 3D movies
should “pop” out of the screen, similar to what audiences experience with 3D
rides at theme parks. Others prefer a more subdued 3D effect that stays behind
the screen, adding a little more depth to the standard 2D fare.

Those who prefer
the reach-out-and-grab-you effect might be partial to Imax Digital 3D, which
the company claims to excel at. Executive Vice President (Technology) of the
Imax Corporation, Brian Bonnick, says that Imax Digital 3D movies “can appear
in front of the screen” which may be more lifelike. He also credits Imax’s
“patented theater geometry”, “proprietary wide-angle lenses” and brighter
images for this effect.

If you’re not a fan
of props being hauled your direction or swords almost touching your nose, then
RealD’s 3D effects could be the alternative. While RealD technology is capable
of extending beyond the screen, the screens used in these cinemas tend to be
flat and positioned further from the viewer, which would minimize the
coming-at-you effect. The 3D effect they produce would also be similar to what
you’d experience on your 3D TV at home. Some videophiles also prefer the 3D
effect to be behind the screen and not protruding from it, so that it does not
serve as a distraction from the movie itself.

However, do keep
in mind that some movies may be shot with effects coming out of the screen for
dramatic effect–the James Cameron epic Avatar would be one example. Other
movies, such as Prometheus by Ridley Scott, are shot with a more subtle effect,
which can be equally believable. So it really isn’t all about the 3D format,
but which movie you’re watching, too.

Is there a
superior format?

Honestly, after
watching a good number of Imax Digital 3D and RealD 3D movies, we’d say that
the 3D effect is very comparable between these two formats. Imax 3D does seem a
bit more dramatic, thanks to the larger screen and closer viewing distance, but
the way the movie was shot is equally important. There are, however, some
notable differences.

Imax screens are
massive and curved, which should help improve your view of the screen and
minimize ghosting–the appearance of a double-images that’s prevalent on some 3D
TVs. Imax Digital 3D screenings should also be consistently brighter. Imax says
that its linear polarizing technology provides an “improved signal-to-noise
performance over circular polarizers” and “allows more light through”. However,
keep in mind that this technology makes 3D movies less tolerant of movements,
especially tilting your head sideways.

RealD 3D typically
provides better viewing angles that allows viewers to tilt and turn their heads
while watching. While 3D movie enthusiasts probably know that keeping their
heads still minimizes ghosting or double-images, young children may not. RealD
representative Rick Heineman believes that this flexibility is important for
moviegoers who should be “free to sit comfortably”.

Another frequently overlooked aspect is
consistency. While RealD theaters are far more abundant, the venues only need
to sport “compliant digital cinema projectors”. This means that your moviegoing
experience would depend on the type of projectors used by the cinema as well as
the sound system installed–these can vary significantly depending on the brands
of equipment used. Imax theaters, however, have to meet standards for audio and
image quality, which means they’ll look and sound more consistent across the
board.

Followers

Barry B. Sandrew, Ph.D.

Founder - Graffiti Video, Inc.

BIOGRAPHY

This is a series of blogs by Barry Sandrew, Ph.D., an internationally recognized inventor, digital imaging expert and visual effects pioneer. Dr. Sandrew is founder of three visual effects facilities that were among the largest and most prolific production studios in Hollywood. Over the past three decades he has been and continues to be instrumental in evolving the entertainment Industry's digital standards and processes in feature filmmaking.

Sandrew earned his doctorate in neuroscience from SUNY at Stony Brook. After winning a 2 year NIH Fellowship at Columbia University, College of Physicians & Surgeons, he joined Harvard Medical School/MGH as staff Neuroscientist. In 1987, Sandrew left his academic and scientific career to found American Film Technologies (AFT) where he invented the first all digital process for colorizing black and white feature films.

At AFT he also invented a paperless animation process used to produce episodic animation for Fox Children's TV and a digital ink & paint and compositing pipeline that produced Spielberg's first digital animated feature film, "We're Back: A Dinosaur Story." Sandrew took AFT public while converting hundreds of movies for clients such as Turner, Disney, Warner Bros., Fox, Gaumont, TF1, ABC, and CBS, among many others.

In 1993 Barry Sandrew left American Film Technologies to co-found Lightspan, an animation and production edutainment studio that grew into one of the largest educational software companies in the U.S., marketing into entire school districts around the country. Lightspan ultimately went public and was later acquired by Plato Learning.

In 2000, Sandrew founded Legend Films, re-inventing colorization and a proprietary film restoration process using the latest in digital imaging technology. Over the course of the next 7 years, Legend Films converted to color approximately 145 black & white films as well as several TV series. Legend Films also produced visual effects for Scorsese's "The Aviator", HBO's "Entourage" and other high profile TV and film projects.

In 2007, with Jim Cameron's game changing "Avatar 3D" scheduled for a 2009 release, Sandrew leveraged his proprietary colorization pipeline, redirecting his company's entire R&D focus to embrace 2D-to-3D conversion and changing the company's name to Legend3D. Since 2010, Legend3D has lead the competitive field, producing 3D conversion and visual effects on over 35 of the highest performing box office tentpole films of the past 6 years.

In 2014, Dr. Barry Sandrew left Legend3D to focus on new immersive and web based media technologies as well his non-profit and for-profit board positions. He is consultant to Fortune 500 companies re: mobile 3D-sensing and motion tracking technology that he considers precursors to augmented reality. Most recently, he is Co-Founder and President/CEO of Graffiti Video, Inc. a company that is redefining the curation of web based media.